The present invention relates to apparatus for preparation of hardenable plastic building materials, such as mortar, and more particularly to improvements in apparatus which are especially suited for continuous preparation of mortar or the like.
It is already known to connect a vessel, wherein the solid and liquid constituents of mortar are brought in contact with each other, to a pump which is intended to evacuate a continuous stream of mortar. The vessel receives solid and liquid constituents (the liquid constituent is normally water) from discrete sources and contains means for mixing the ingredients so that a constant supply of mortar is available for evacuation by the pump. A drawback of such apparatus is that the pump often causes damming or choking of the chamber with the result that the rate or evacuation from the chamber fluctuates within a rather wide range. This, in turn, causes certain batches of solid constituents to contain more water than the others. The output of the pump increases considerably when the pump evacuates a batch which contains a relatively high percentage of water, and this affects the uniformity or homogeneousness of mixture in the chamber.